RAD52 Adjusts Repair of Single-Strand Breaks via Reducing DNA-Damage-Promoted XRCC1/LIG3α Co-localization
Jian Wang,
You-Take Oh,
Zhentian Li,
Juan Dou,
Siyuan Tang,
Xiang Wang,
Hongyan Wang,
Shunichi Takeda,
Ya Wang
Affiliations
Jian Wang
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
You-Take Oh
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
Zhentian Li
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
Juan Dou
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
Siyuan Tang
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
Xiang Wang
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
Hongyan Wang
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
Shunichi Takeda
CREST Research Project, Radiation Genetics, Faculty of Medicine, Kyoto University, Yoshida-konoe, Sakyo-ku, Kyoto 606-8501, Japan; Corresponding author
Ya Wang
Department of Radiation Oncology, Emory University School of Medicine and the Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA; Corresponding author
Summary: Radiation sensitive 52 (RAD52) is an important factor for double-strand break repair (DSBR). However, deficiency in vertebrate/mammalian Rad52 has no apparent phenotype. The underlying mechanism remains elusive. Here, we report that RAD52 deficiency increased cell survival after camptothecin (CPT) treatment. CPT generates single-strand breaks (SSBs) that further convert to double-strand breaks (DSBs) if they are not repaired. RAD52 inhibits SSB repair (SSBR) through strong single-strand DNA (ssDNA) and/or poly(ADP-ribose) (PAR) binding affinity to reduce DNA-damage-promoted X-Ray Repair Cross Complementing 1 (XRCC1)/ligase IIIα (LIG3α) co-localization. The inhibitory effects of RAD52 on SSBR neutralize the role of RAD52 in DSBR, suggesting that RAD52 may maintain a balance between cell survival and genomic integrity. Furthermore, we demonstrate that blocking RAD52 oligomerization that disrupts RAD52’s DSBR, while retaining its ssDNA binding capacity that is required for RAD52’s inhibitory effects on SSBR, sensitizes cells to different DNA-damaging agents. This discovery provides guidance for developing efficient RAD52 inhibitors in cancer therapy.
